A very basic question, I know, but I thought others would have some great insight on this... Especially with index's, the market almost always defaults to making a new price. Logic would say this is because things are always growing everyday - more people are being born, etc. As a result, intraday systems generally do better going long than short - and even sometimes loose money on shorts, even when the equations are adjusted for short trading. This notion seems to be especially true with commodities, where things are almost always trending in a direction everyday. Forex seems to be a whole different ball game, where it's difficult to decide just on raw data.